The imprinted expression of the IGF2 and H19 genes is controlled by the imprinting control region 1 (ICR1) located at chromosome 11p15.5. This methylation-sensitive chromatin insulator works by binding the zincfinger protein CTCF in a parent-specific manner. DNA methylation defects involving the ICR1 H19/IGF2 domain result in two growth disorders with opposite phenotypes: an overgrowth disorder, the Beckwith– Wiedemann syndrome (maternal ICR1 gain of methylation in 10% of BWS cases) and a growth retardation disorder, the Silver–Russell syndrome (paternal ICR1 loss of methylation in 60% of SRS cases). Although a few deletions removing part of ICR1 have been described in some familial BWS cases, little information is available regarding the mechanism of ICR1 DNA methylation defects. We investigated the CTCF gene and the ICR1 domain in 21 BWS patients with ICR1 gain of methylation and 16 SRS patients with ICR1 loss of methylation. We identified four constitutional ICR1 genetic defects in BWS patients, including a familial case. Three of those defects are newly identified imprinting defects consisting of small deletions and a single mutation, which do not involve one of the CTCF binding sites. Moreover, two of those defects affect OCT-binding sequences which are suggested to maintain the unmethylated state of the maternal allele. A single-nucleotide variation was identified in a SRS patient. Our data extends the spectrum of constitutive genetic ICR1 abnormalities and suggests that extensive and accurate analysis of ICR1 is required for appropriate genetic counseling in BWS patients with ICR1 gain of methylation.
Demars, J., Mansur Ennuri Moftah Shmela, S. Rossignol, J. Okabe, I. Netchine, S. Azzi, S. Cabrol, C. Le Caignec, A. David , Y. Le Bouc, A. El-Osta , C. Gicquel(9-2010)

Marine macroalgae are considered as an excellent source of bioactive compounds which has a broad range of biological activities including antibacterial and antioxidant. Crude methanolic and water extracts of 19 marine algal species (6 Chlorophyta, 8 Phaeophyta and 5 Rhodophyta) collected from the western coast of Libya were evaluated for antibacterial activity against pathogenic bacteria (4 Gram-positive, 4 Gram-nega- tive). The extracts showed a significant antibacterial activity against Gram positive (Staphylococcus aureus, Bacillus subtilis, Bacillus spp., and Staphylococcus epidermidis) as well as Gram negative bacteria (Escherichia coli, Salmonella typhi, Klebsiella spp., and Pseudomonas aerugi- nosa). The algal aqueous and methanolic extracts displayed different degrees of antimicrobial activities against different bacteria, in some cases methanolic extracts showed higher antibacterial activity than aqueous extracts. Among tested algae, Brown algae namely Cystoseira crinite exhibited the highest antibacterial activity among tested algal species.
Salah M. Azwai(1-2013)

The transcriptional changes that occurred in Salmonella enterica serovar Enteritidis during colonization of the alimentary tract of newly hatched chickens were studied. A whole genome oligonucleotide microarray was used to compare the expression pattern with that from bacteria cultured in nutrient broth in vitro. Amongst other changes Salmonella Pathogenicity Island (SPI)-1, SPI-2 and SPI-5 genes were up-regulated in vivo suggesting a close association with the mucosa during colonization. Particular attention was paid to genes associated with metabolism of dicarboxylic acids and to responses to high osmolarity. Association between the colonization phenotype and gene mutations indicated that the latter was more important as a contribution to the colonization phenotype. arabic 12 English 89
Abdulgader Dhawi, Elazomi A, Jones M A, Lovell M A, Li H, Emes R D, Barrow P A(7-2011)